Brake shoe gauge



April 2,1935. RDCHASE HAL 1,996,323

/ BRAKE SHOE GAUGE Filed Feb. 25, 1931 2 Sheets-Sheet 1 3- 67456 fiao Zai J UZaazz April 2, 1935. R. D. CHASE ET AL 1,996,323

BRAKE SHOE GAUGE Filed Feb. 25, 1951 2 Sheets-Sheet 2 Patented Apr.'2,1935 "UNITEDS'TATES PATENT OFFICE BRAKE SHOVE 'GAUGE Russell D. Chaseand Rudolph J. lson,

Summit, 11]. Application February 25, 1931, Serial No. 518,233

' 4 Claims. 01; 23-180 Our invention relates to automobile brakes andmore particularly to appliances for determining the amount of clearancebetween the brake shoe and drum, and our main object is to provide anappliance of this kindv which facilitates the uni- ,fori'n adjustment ofthe brake shoe- A further object-ofthe invention is to adapt the novelgauge tothe conventional internal brake *for the purpose of supplantingthe common gauge now in use. 1

A still further object of the invention is to design the novel gaugewith a support which is .readily applicable to the conventional brakedrum, eliminating the necessity of; special attachments for or radicalchanges in the design 0f the brake drum.

Another object of the invention is to locate the control of the novelgauge by way of a per ;foration in the rimof the brake drum.

An additional object of the invention is to so apply the novel gauge asto have it in a fixed .and easily viewed position while all of the shoesin a given brake are adjusted.

A .final but nevertheless important object of the invention is to designthe novel gauge with parts which are few, simple and of ruggedconstruction.

With the above objects in view and any others that may suggestthemselves from the specification'and claims to follow, a betterunderstanding of the invention may be had by reference to theaccompanying, drawings, in which-- Fig. 1 is an elevation of the topfragment of a typical brake drum as viewed from the outer side of theautomobile, the novel gauge being shown as mounted;

. Fig. 2 is a sideview of the embodiment in Figure .1, taken from theleft, and showing the brake in section; j r

;Fig. 3 is a detail section on the line ii3 of .Fig. 2;

Figs-4 and 5 are,respectively, aside view and .frontview of amodification; and r s I 7 7 Figs. 6 and 7, are, respectively, asectional side view and a fragmentalplan view of another modification rSince the advent of four-wheel brakes for automobiles, and especiallyinternal brakes having two -or more shoes in each brake, the matter ofadjusting the shoes has become morecomplicatged. It will be realizedthat his insuflicient to equalize the four .brakes a machine, withoutadjusting each brake individually to secure the uniform application ofits shoes to the drum. With automobiles designed for high speed, thisadjustment should beas nearly accurate as pos- If gauge of this kind sofrequently taxes the patience of the mechanic that he soon decides togetalong without it, simply depending on his own judgment whether theadjustmentis sufr-Ji I ficient. Usually, if the shoe does not""gra the Imechanic is satisfied that theadjustment iscompleted', the relations ofthe toe or 'heel of the particular shoe to the-drum being problematical.'As a matter of fact, these relations are of prime importance, since theengaging surfaceof the shoe depends largely for itsarea upon theadjustment of the toe and heel of the shoe-relative to the brakedrum.yThe latter running in a per- ,fect circle, generally speaking, isconsidered as a constant, and thatxbrake is efiicient which engages amaximum of shoe surface with drum.-

' In carrying out the invention, particular reference may first be hadto Figures 1 m3 ofthe drawings In; these figures, the conventional brakedrum is-indicated-at ll and is peripheral flange :at 10a. Drums of thistype are for internal-brake use, :and are usually made with a slot bywayof. which a standard ieelergauge is insertable, and a tapped perforation10b for. a screw which secures a dust cap over the. slot I make use ofthis perforation to attach a base block I -l to the face;

whilethe brake is in use.

of the drum, this block being countersunk to receivea 'bolt l2 flushly,and the latter screwing into the perforation to firmly secure-the blockto the brake drum. The block is preferablyiextended to fit over thetopcurvatureof the drum as indicated at Main Fig. 2, so as to secure asnug fit of the blcck'with the drum.

Shortly below the bolt l2, the block I l is horizontally perforated witha tapped here to receive a screw I3 from the front. Betweenthe head'ofthe screw and the block is a plate 14 which is-perforated' with avertical slot Mai to permit the passageof thebolt shank. Thus, the

relation of the plate with theblock is suchthat by slightly looseningthe screw l3, the plate [4 .fianges Mb which receivebetween themabracket l lc whose upper portion is perforated for the angularadjustment, and the bolt lfia the passage of a tubular housing [5. Thelower part of the bracket is clamped-t0 and pivotally adjustable in theplate flanges Mb by a cross bolt l6. One side of the bracket is alsoextended forwardly, and the extension is formed with a companion jaw Mdabout the tubular housing, with a. cross bolt 16a to clamp the housingto the extension. The bolt 16 therefore holds the longitudinal one, ofthe housing I5.

The tubular housing [5 extends rearwardly to a point over the center ofthe drum flange Illa and has journaled within it a shaft I 617. The rearend of the shaft projects from the housing to be extended with a radialarm [1, the outer end of this arm being vertically tapped for a threadedpin I8. The latter has a knurled head [8a at its upper end and receivesa coil spring [8b between the arm and the head. Thus, the head may beused for the vertical adjustment of the pin to project a greater orlesser distance from below the arm ll, the spring l8b serving to engagethe head |8a frictionally whereby to maintain the pin in any position towhich it has been adjusted; For the purposes of our gauge, we haveseenfit to perforate the flange Illa of the brake drum with a tapped borelDc, through which the lower portion of the pin I 8 is adapted to pass,and which is of a larger diameter than the pin that the latter mayfreely clear the flange. Figure 2 shows the relation of the pin l8 withthe drum flange, and indicates that the lower end of the pin [8 is incontact with the shoe llld of a braking unit Hie. When our gauge is notapplied, a short screw or plug may be applied to the perforation Illa toclose it and prevent access of water or dust to the interior of thebrake drum.

Frontally of the bracket M, the tubular housing l5 extends a suitabledistance for handy access by the mechanic, receiving a bracket l9 bysuitable clamping means 20. The bracket extends in an upward directionand has fastened to it at 2| a standard dial gauge 22. This type ofgauge has its dial adjustable in a rotary direction by means of theknurled rim 22a; and

the pointer 22b of the gauge is controlled by the movement of a plunger23 which extends from the gauge and is projected to a predeterminedlimit by the force of a spring within the gauge. In the presentembodiment, the plunger 23 extends downwardly to meet a finger 2dradially extended from the frontal end of the shaft 161) where thelatter projects from the tubular housing l5. As both the radial arm I!and the radial finger 24 are fixed to the shaft-and projected parallelto each otherit will be seen that any movement imparted the pin l8 bythe tionto the testing of the brake, it is necessary to turn the brakedrum and its gauge attachment to a point where the pin is opposite thetoe of a given; brake unit within the drum. Now,

the brake is applied fully, which action induces a. correspondingmovement in the pointer 22a ofthegauge. Now the dial of the gauge isturned 'to locate the zero legend of its scale in line with the pointer.When the brake is now re- ,leased, the amount of travel ofthe pointerwill indicate relatively the amount. of departure of the shoe toe fromthe drum flange. By calibrating the gauge scale to represent thousandthsor other fractions of an inch in the movement of the pin l8, the amountof clearance is determined between the shoe toe and the drum flange andthe braking unit adjusted to increase or decrease this amount asstandards of clearance dictate. A similar operation ensues when the drumis given a further turn to line the pin 18 up with the heel of the sameshoe; and, should the latter adjustment in any way prejudice the firstone, a brief return movement of the testing apparatus may be made tocheck up before the adjustment of the shoe is considered terminated. Itis thus seen that when the novel gauge is once attached to a brake drum,it may remain in place until the shoes of each braking unit are testedand properly adjusted. Obvious- 7 ly, the adjustment of the plate HZwith the block H is for the purpose of properly alining the pin it)relative to the perforation I00 or to take up any irregluarity orinaccuracy in that respect.

In the modification of Figures 4 and 5, the frontal part of theattachment is changed to directly connect the gauge with the shafthousing I5; Thus, the gauge is made with an ofiset hub 220 which isattached directly to the front end of the tubular housing IS, the shaftlBb extending into the gauge to operate the same as indicated by dottedlines'in Fig. 5, this being another method by which gauges of this kindare operated. This modification is desirable for reasons of compactness.

The modification of Figures 6 and 7 is designed with the gauge in apendent position relative to the main embodiment, the shaft I62) beingreplaced by a lever 25 medially pivoted at 26 in the tubular housing IS.The rear end of the lever 25 receives a pin similar to the correspondingstructure in the main embodiment, although a lock nut 21 for the pin hasbeen added to make up for lack of sufiicient bearing for the pin. Thefront end of the lever 25' is slightly convexed as indicated at 25a forsuitable contact with the gauge plunger 23 when the lever assumes anangular position. It will be obvious from Fig. 6 that the movement ofthe pin l8 will be transmitted by a pivotal action to the plunger 23.This modification is desirable in an alternative sense, and also to doaway with the provision of the shaft and bearings therefor.

It will be seen that a gauge constructed on the lines described is avaluable adjunct for the scientific adjustment of automobile brakes. Thedial reflects unfailingly the exact amount of clearance of the brakeshoe at any portion of its surface, and it is an easy matter todetermine to an accurate degree the condition of the brake before andafter it is adjusted, making it possible for the mechanic to knowexactly what to do for each unit in the brake and to guarantee theadjustment of each brake to regulation requirements. The novel gauge isa radical departure from the conventional feeler gauge which is easilyconfused when a number of gauges of different values are about,resulting in mistakes. Also, the feeler gauge is a thing which is hardto pick up oi the floor between ones fingers on account of its thinness,and frequently becomes twisted or distorted when the brake drum isturned, making it necessary to get a new gauge to complete the job.Finally, the novel gauge is an article which is simple, compact, and ofa rugged nature so as to be handled with ease by anyone and to operateefficiently for long periods.

We claim:-

1. A tester for a brake including a peripherally-perforated drumcomprising, a support at-' a companion jaw formed about the housing fromtachable to the drum, an indicator applicable to the brake shoe by wayof the drum perforation and including a tubular housing, a bracketslidably disposing the latter and pivotally connected to the support,means to fix the pivotal adjustment of the bracket, an extension of thelatter, and a clamp co-operating with the extension to fix thelongitudinal adjustment of the housing.

2. The structure of claim 1, and spaced flanges extended from thesupport and receiving the bracket therebetween to make said'pivotalconnection.

3. The structure of claim 1, the extension being alongside the housing,and the clamp being v the extension.

4. A testing device for brakes comprising means for attaching the deviceto the headof a brake drum, said device including a bracket structurepivoted to said means for mounting. the same for H movement about ahorizontal axis, a feeler pin and a gauge connected therewith carried bythe bracket structure, the latter including means for adjusting the pinand gauge axially of the brake drum, said pin arranged to contact theperiphery of the brake shoe with the gauge measuring the peripheralclearance of the brake

